He criticized the risk management methods used by the finance industry and warned about financial crises, subsequently profiting from the late-2000s financial crisis.[5][6] He advocates what he calls a "black swan robust" society, meaning a society that can withstand difficult-to-predict events.[7] He proposes antifragility in systems, that is, an ability to benefit and grow from a certain class of random events, errors, and volatility[8] as well as "convex tinkering" as a method of scientific discovery, by which he means that decentralized experimentation outperforms directed research.[9]

Finance view

Taleb considers himself less a businessman than an epistemologist of randomness, and says that he used trading to attain independence and freedom from authority.[20] Taleb was a pioneer of tail risk hedging (now sometimes called "black swan protection"),[21] which is intended to mitigate investors' exposure to extreme market moves. His business model has been to safeguard investors against crises while reaping rewards from rare events, and thus his investment management career has included several jackpots followed by lengthy dry spells.[10]

Taleb reportedly became financially independent after the crash of 1987[10] and was successful during the Nasdaq dive in 2000[24] as well as the financial crisis that began in 2007,[25] a development which he attributed to the mismatch between statistical distributions used in finance and reality. Following this crisis, Taleb became an activist for what he called a "black swan robust society".[26][27] Since 2007 Taleb has been a Principal/Senior Scientific Adviser at Universa Investments in Santa Monica, California, a fund which is based on the "black swan" idea, owned and managed by former Empirica partner Mark Spitznagel. Some of its separate funds made returns of 65% to 115% in October 2008.[5][28] In a 2007 Wall Street Journal article, Taleb claimed he retired from trading in 2004, and became a full-time author.[29][contradictory][30] However, Taleb describes the nature of his involvement as 'totally passive' from 2010 on.[31]

In late 2015 Nassim, along with Robert J. Frey and Raphael Douady, formed the Real World Risk Institute “to build the principles and methodology for what we call real-world rigor in decision making and codify a clear-cut way to approach… to provide executive education courses and issue two certificates.” [39]

Writing career

Taleb's four volume philosophical essay on uncertainty, titled the Incerto, covers the following books: Fooled by Randomness (2001), The Black Swan (2007–2010), The Bed of Procrustes (2010), and Antifragile (2012).

His first non-technical book, Fooled by Randomness, about the underestimation of the role of randomness in life, published in 2001, was selected by Fortune as one of the smartest 75 books known.[40]

The fourth book of his Incerto series—Antifragile: Things That Gain from Disorder—was published in November 2012.[44] In the introduction of the book, Taleb describes it as follows: "Some things benefit from shocks; they thrive and grow when exposed to volatility, randomness, disorder, and stressors and love adventure, risk, and uncertainty. Yet, in spite of the ubiquity of the phenomenon, there is no word for the exact opposite of fragile. Let us call it antifragile. Antifragility is beyond resilience or robustness. The resilient resists shocks and stays the same; the antifragile gets better."[44]:3 (A mathematical parallel version of the Incerto Quadrilogy is available on Taleb's website.[45])

Taleb's non-technical writing style has been described as mixing a narrative, often semi-autobiographical style with short philosophical tales and historical and scientific commentary. The sales of Taleb's first two books garnered an advance of $4 million for a follow-up book on anti-fragility.[10]

Ideas and theories

Taleb's book The Bed of Procrustes summarizes the central problem: "we humans, facing limits of knowledge, and things we do not observe, the unseen and the unknown, resolve the tension by squeezing life and the world into crisp commoditized ideas". Taleb disagrees with Platonic (i.e., theoretical) approaches to reality to the extent that they lead people to have the wrong map of reality rather than no map at all.[19] He opposes most economic and grand social science theorizing, which in his view suffer acutely from the problem of overuse of Plato's Theory of Forms. Based on these and other constructions, he advocates for what he calls a "black swan robust" society, meaning a society that can withstand difficult-to-predict events.[7]

He has also proposed that biological, economic, and other systems exhibit an ability to benefit and grow from volatility—including particular types of random errors and events—a characteristic of these systems that he terms antifragility.[46] Relatedly, he also believes that universities are better at public relations and claiming credit than generating knowledge. He argues that knowledge and technology are usually generated by what he calls "stochastic tinkering" rather than by top-down directed research,[47]:182 and has proposed option-like experimentation as a way to outperform directed research as a method of scientific discovery, an approach he terms convex tinkering.[44]:181ff, 213ff, 236ff

Taleb has called for cancellation of the Nobel Prize in Economics, saying that the damage from economic theories can be devastating.[48] He opposes top-down knowledge as an academic illusion and believes that price formation obeys an organic process.[49] Together with Espen Gaarder Haug, Taleb asserts that option pricing is determined in a "heuristic way" by operators, not by a model, and that models are "lecturing birds on how to fly".[49] Teacher and author Pablo Triana has explored this topic with reference to Haug and Taleb,[50] and says that perhaps Taleb is correct to urge that banks be treated as utilities forbidden to take potentially lethal risks, while hedge funds and other unregulated entities should be able to do what they want.[51]

Taleb's writings discuss the error of comparing real-world randomness with the "structured randomness" in quantum physics where probabilities are remarkably computable and games of chance like casinos where probabilities are artificially built.[52] Taleb calls this the "Ludic fallacy". His argument centers on the idea that predictive models are based on Plato's Theory of Forms, gravitating towards mathematical purity and failing to take some key ideas into account, such as: the impossibility of possessing all relevant information, that small unknown variations in the data can have a huge impact, and flawed theories/models that are based on empirical data and that fail to consider events that have not taken place but could have taken place. Discussing the Ludic fallacy in The Black Swan, he writes, "The dark side of the moon is harder to see; beaming light on it costs energy. In the same way, beaming light on the unseen is costly in both computational and mental effort."

In the second edition of The Black Swan, he posited that the foundations of quantitative economics are faulty and highly self-referential. He states that statistics is fundamentally incomplete as a field as it cannot predict the risk of rare events, a problem that is acute in proportion to the rarity of these events. With the mathematician Raphael Douady, he called the problem statistical undecidability (Douady and Taleb, 2010).

Taleb sees his main challenge as mapping his ideas of "robustification" and "antifragility", that is, how to live and act in a world we do not understand and build robustness to black swan events. Taleb introduced the idea of the "fourth quadrant" in the exposure domain.[53] One of its applications is in his definition of the most effective (that is, least fragile) risk management approach: what he calls the 'barbell' strategy which is based on avoiding the middle in favor of linear combination of extremes, across all domains from politics to economics to one's personal life. These are deemed by Taleb to be more robust to estimation errors. For instance, he suggests that investing money in 'medium risk' investments is pointless because risk is difficult if not impossible to compute. His preferred strategy is to be both hyper-conservative and hyper-aggressive at the same time. For example, an investor might put 80 to 90% of their money in extremely safe instruments, such as treasury bills, with the remainder going into highly risky and diversified speculative bets. An alternative suggestion is to engage in highly speculative bets with a limited downside.

Taleb asserts that by adopting these strategies a portfolio can be "robust", that is, gain a positive exposure to black swan events while limiting losses suffered by such random events.[54] Together with Donald Geman and Hélyette Geman, he modeled the "maximum entropy barbell" which consists in "to constrain only what can be constrained (in a robust manner) and to maximize entropy elsewhere", based on an insight by E.T. Jaynes that economic life increases in entropy under regulatory and other constraints.[55] Taleb also applies a similar barbell-style approach to health and exercise. Instead of doing steady and moderate exercise daily, he suggests that it is better to do a low-effort exercise such as walking slowly most of the time, while occasionally expending extreme effort. He avers that the human body evolved to live in a random environment, with various unexpected but intense efforts and much rest.[56]

Besides his work on finance and probability, Taleb touches upon many current issues such as employment,[57] the state of academia,[58] and the Syrian War.[59]

Praise and criticism

In a 2008 article in The Times, the journalist Bryan Appleyard described Taleb as "now the hottest thinker in the world".[18] The Nobel Laureate Daniel Kahneman proposed the inclusion of Taleb's name among the world's top intellectuals, saying "Taleb has changed the way many people think about uncertainty, particularly in the financial markets. His book, The Black Swan, is an original and audacious analysis of the ways in which humans try to make sense of unexpected events."[60] Taleb was treated as a "rock star" at the World Economic Forum annual meeting in Davos in 2009; at that event he had harsh words for bankers suggesting that "it is time for some punishment".[61]

Taleb contends that statisticians can be pseudoscientists when it comes to risks of rare events and risks of blowups, and mask their incompetence with complicated equations.[62] This stance has attracted criticism: the American Statistical Association devoted the August 2007 issue of The American Statistician to The Black Swan. The magazine offered a mixture of praise and criticism for Taleb's main points, with a focus on Taleb's writing style and his representation of the statistical literature. Robert Lund, a mathematics professor at Clemson University, writes that in Black Swan, Taleb is "reckless at times and subject to grandiose overstatements; the professional statistician will find the book ubiquitously naive."[63]

Aaron Brown, an author, quant and finance professor at Yeshiva and Fordham Universities, said that "the book reads as if Taleb has never heard of nonparametric methods, data analysis, visualization tools or robust estimation."[64] Nonetheless, he calls the book "essential reading" and urges statisticians to overlook the insults to get the "important philosophic and mathematical truths." Taleb replied in the second edition of The Black Swan that "One of the most common (but useless) comments I hear is that some solutions can come from 'robust statistics.' I wonder how using these techniques can create information where there is none".[65] While praising the book, Westfall and Hilbe in 2007 complained that Taleb's criticism is "often unfounded and sometimes outrageous."[66] Taleb, writes John Kay, "describes writers and professionals as knaves or fools, mostly fools. His writing is full of irrelevances, asides and colloquialisms, reading like the conversation of a raconteur rather than a tightly argued thesis. But it is hugely enjoyable – compelling but easy to dip into. Yet beneath his rage and mockery are serious issues. The risk management models in use today exclude the very events against which they claim to protect the businesses that employ them. These models import a veneer of technical sophistication... Quantitative analysts have lulled corporate executives and regulators into an illusory sense of security."[67] Taleb felt that academics showed "bad faith" by criticizing a literary book that claimed to be a literary book and by ignoring the empirical evidence provided in his appendix and more technical works.[68] However, Berkeley statistician David Freedman said that efforts by statisticians to refute Taleb's stance have been unconvincing.[69]

Taleb and Nobel laureate Myron Scholes have traded personal attacks, particularly after Taleb's paper with Espen Haug on why nobody used the Black–Scholes–Merton formula. Taleb said that Scholes was responsible for the financial crises of 2008, and suggested that "this guy should be in a retirement home doing Sudoku. His funds have blown up twice. He shouldn't be allowed in Washington to lecture anyone on risk."[27] Scholes retorted that Taleb simply "popularises ideas and is making money selling books". Scholes claimed that Taleb does not cite previous literature, and for this reason Taleb is not taken seriously in academia.[70] Haug and Taleb (2011) listed hundreds of research documents showing the Black–Scholes formula was not Scholes' at all, and argued that the economics establishment ignored literature by practitioners and mathematicians (such as Ed Thorp), who had developed a more sophisticated version of the formula.[71]

Citing his academic works on the same topics covered in The Black Swan, Taleb said that "Academics should comment on data there, not make technical comments on a literary book".[72] He has said that no direct published criticism has been directed at his ideas, but rather at his person and style. He wrote, "you never win an argument until they attack your person."[73] In an interview on Charlie Rose, Taleb said that he was pleased that none of the criticism he received for The Black Swan had any substance, as it was either unintelligent, ad hominem, or style over substance, which convinced him to "go for the jugular" with a huge financial bet on the breakdown of statistical methods in finance.[74]

Taleb's aggressive and clearly directed commentary against parts of the finance industry—e.g., stating at Davos in 2009 that he was "happy" that Lehman Brothers collapsed—has led to reports of personal attacks and possible threats.[75]

Taleb received an honorary doctorate from the American University of Beirut in 2016 and also gave a memorable commencement address to the graduating class in which describing his life stated:

I hesitate to give advice because every major single piece of advice I was given turned out to be wrong and I am glad I didn’t follow them. I was told to focus and I never did. I was told to never procrastinate and I waited 20 years for the Black Swan and it sold 3 million copies. I was told to avoid putting fictional characters in my books and I did put in Nero Tulip and Fat Tony because I got bored otherwise. I was told to not insult the New York Times and the Wall Street Journal, the more I insulted them the nicer they were to me and solicit Op-Eds. I was told to avoid lifting weights for a back pain and became a weightlifter: never had a back problem since.

If I had to relive my life I would be even more stubborn and uncompromising than I have been. One should never do anything without skin in the game. If you give advice, you need to be exposed to losses from it.[76]

Derbyshire, J., & Wright, G. (2014). Preparing for the future: development of an ‘antifragile’methodology that complements scenario planning by omitting causation. Technological Forecasting and Social Change, 82, 215-225.

Simply, one observation in 10,000, that is, one day in 40 years, can explain the bulk of the "kurtosis", a measure of what we call "fat tails", that is, how much the distribution under consideration departs from the standard Gaussian, or the role of remote events in determining the total properties. For the U.S. stock market, a single day, the crash of 1987, determined 80% of the kurtosis. The same problem is found with interest and exchange rates, commodities, and other variables. The problem is not just that the data had "fat tails", something people knew but sort of wanted to forget; it was that we would never be able to determine "how fat" the tails were. Never. The implication is that those tools used in economics that are based on squaring variables (more technically, the Euclidean, or L2 norm), such as standard deviation, variance, correlation, regression, or value-at-risk, the kind of stuff you find in textbooks, are not valid scientifically (except in some rare cases where the variable is bounded). The so-called "p values" you find in studies have no meaning with economic and financial variables. Even the more sophisticated techniques of stochastic calculus used in mathematical finance do not work in economics except in selected pockets.